1. Field
The present inventive concepts relate to a diffraction-based overlay (DBO) mark and methods of overlay measurement.
2. Description of Related Art
In a process of manufacturing a semiconductor device, an exposure process may be performed to form a micropattern on a semiconductor substrate. Such an exposure process may include a process of forming a photoresist pattern on a semiconductor substrate, measuring an alignment state of the formed photoresist pattern, and determining a follow-up process according to alignment errors.
The process of measuring an alignment state of a photoresist pattern on a semiconductor substrate may be performed by a process of measuring an overlay error. Such an overlay error measurement process may allow for confirmation as to whether a pattern (for example, a photoresist) disposed on an upper lower of a semiconductor substrate is accurately aligned with respect to a pattern (for example, an insulator, a semiconductor, or a metal) disposed on a lower layer of the semiconductor substrate.